Infrared remote control switch circuit diagram composed of CD4017

Most lighting circuits in today's buildings use hidden wires. If a 4-wire electronic switch is used to control these lighting lamps, another power supply must be connected and the circuit must be modified. The project is time-consuming and labor-intensive, and affects the appearance. Today we are going to design and produce a single-wire infrared remote control switch. It has only a single incoming line and a single outgoing line, and can directly replace the wall switch that is very popular in the home. It is very convenient to install and replace; it can also be easily controlled remotely.

1. Performance introduction:

The advantages of this circuit are: ⑴ The circuit uses the principle of current transformer to boost the voltage, and uses diodes to limit and stabilize the voltage, which cleverly solves the problem of power supply of the switch itself; ⑵ It has a wide range of applications and can be used with the remote control of a color TV or DVD player. The remote control ⑶ also has the advantages of small voltage drop and low power consumption.

2. Working principle:

As shown in the figure, the AB terminal on the left side of the circuit is the single-wire input and output terminal, which is connected in series with the load and then connected to the 220V mains. The integrated block CD4017 is connected into a bistable trigger circuit to control the one-way thyristor; the SCR is used as a switch to control the on-off of the load, and the thyristor conduction is equivalent to the switch closing; the micro-transformer B1 is used to solve the electronic switch conduction problem. The diodes D1 and D2 are connected in parallel to the primary of the transformer to limit the primary voltage to about 0.7V, which can prevent the primary coil of the micro transformer from burning out and prevent the output voltage from being too high due to excessive load current.

When the infrared receiving head receives the infrared remote control signal, it outputs a negative pulse. After reaching the phase through the transistor T1, it forms a pulse width gate circuit through R3 and C2 and inputs it to the pulse input terminal 14 of the IC. The integrated block IC is connected to a bistable trigger circuit, and the state of pin ② of the output terminal flips once every time a pulse is input, thereby achieving on and off control.

When the switch is turned off: the ② pin of IC1 is low level, the thyristor is cut off, and the load is powered off. At this time, the mains power is rectified by the full-bridge Q1, and then divided by the resistor R1 to provide low-voltage direct current to the electronic switch, ensuring the supply of standby power.

When the switch is turned on, the output pin ② of IC1 is at high level, and the thyristor is triggered to turn on, which is equivalent to the switch being closed, and the load is powered and operates normally. If there is current flowing in the load circuit, there must be current flowing through the primary coil of the transformer. The voltage is boosted by the micro transformer and then rectified by the full bridge Q2, which can also provide low-voltage DC power to the electronic switch.

It can be seen that whether the electronic switch is on or off, it can solve the problem of self-power supply of the electronic switch circuit. Each time the remote control is pressed, the state of the electronic switch will change, thereby realizing the function of the remote control switch.

3. Equipment selection and debugging:

1. The thyristor, diode and bridge stack in the picture should be selected according to the load current, and the breakdown voltage should be above 400V.

2. Micro transformer B1 uses a micro core below EE12. During production, the number of coil turns and the turns ratio can be adjusted to make the secondary output voltage meet the circuit requirements. For example, if the output voltage is required to be 5V, then the turns ratio between primary and secondary is generally selected to be around 1:10.

3. The infrared receiver should use an integrated receiver with negative pulse output. It is best to install a metal shield to improve the anti-interference ability.